LINCOLN, Neb. (AP) — A Nebraska state lawmaker slated to leave office next month because of term limits has stepped down early.

Former Sen. Tyson Larson, of O’Neill, announced his resignation in a letter Wednesday to Gov. Pete Ricketts.

Larson has represented the mostly rural 40th legislative district in northeastern Nebraska since 2011. He will be replaced by Tim Gragert, of Creighton, who is set to take office when a new legislative session begins next month.

Larson doesn’t say why he’s stepping down early. He describes his experience in the Legislature as a humbling, valuable experience.

Larson served as chairman of the General Affairs Committee. He faced criticism for spending a lot time in Omaha instead of his district, which he says was necessary to care for his son during a custody battle.